[Biomphalaria havanensis and Biomphalaria orbignyi (Pulmonata: Planorbidae). 2 species in synonymy?]. / Biomphalaria havanensis y Biomphalaria orbignyi (Pulmonata: Planorbidae). Dos especies en sinonimia?

Morphometrics differences of 2 species of the genus Biomphalaria in Cuba (B. havanensis and B. orbignyi) were studied. These are potential intermediate hosts of schistosomiasis whose taxonomic location has been discussed. Of the variables measured the following coefficients were compared (length of the sheath of the penis/length of prepuce, caudal distance/cephalic distance, diameter of the shell/width of the shell) with the use of univariate and multivariate tests. Both tests proved that the length of the prepuce is the variable which discriminate best between both groups. These results complement other aspects which advocate for the taxonomic separation of these 2 species of planorbids [correction of plororbis].

[Importance of Tarebia granifera in the control of a population of Biomphalaria peregrina introduced in Cuba]. / Importancia de Tarebia granifera en el control de una población introducida de biomphalaria peregrina en Cuba.

It was observed that the Tarebia granifera plays a significant role in the control of a Biomphalaria peregrina population introduced in a permanent water body. The densities of this planorbid, which had reached high levels, were notably reduced by two important events: an increase of the water level due to heavy rains, and the introduction of the competitor, whose effectiveness had been tested in a different habitat. Knowledge on the ecology and biology of the competitor and the host in permanent water bodies helped to elaborate the measures of control which led to the reduction of the host densities while those of the competitor increased.

[Anatomy and morphometry of Physa cubensis Pfeiffer, 1839 (Pulmonata: Physidae) in Cuba]. / Anatomía y morfometría de Physa cubensis Pfeiffer, 1839 (Pulmonata: Physidae) en Cuba.

The anatomic description of Physa cubensis, based on specimens collected in 5 different sites in Cuba, is presented. The anatomic characteristics of the reproductive system as well as mantle digitations give ground for affirming that this is a unique species with external morphological variations and thus it should be kept under the Physa genre. Besides, dispersion diagrams and regression lines of the length in the width were analyzed in the five sites; the L/A (length/width) variation quotient was compared using a variance analysis. Significant differences were observed in the different sites probably due to the feeding sources of each biotope.

[A computer program for the geographic distribution of fluvial mollusks of medical interest in Cuba]. / Un programa de computadora para la distribución geográfica de moluscos fluviales de importancia médica en Cuba.

The need to know the distribution of mollusks considered to play an important medical role in Cuba through a geographic representation motivated us to develop a software capable of acting as a system for the retrieval of geographic information in which the requested data would be presented in maps. The system has been called DMIM and it is a useful tool for malacological studies, and assessment and planning of programs for the control of intermediate host mollusks, as well as for teaching purposes.

[Laboratory studies of the molluscacidal action of the maguey (Agave legrelliana) on Biomphalaria havanensis]. / Estudios de la acción molusquicida en el laboratorio del maguey (Agave legrelliana), sobre Biomphalaria havanensis.

A study was carried out on the molluscacidal action of agave (Agave legrelliana) on the mollusk Biomphalaria havanensis, host of Schistosoma. Different concentrations of the plant's juice extract were tested to determine lethal doses. 3 experimental series were carried out using 144 mollusks in each. LD50 = 0.14 mL/L and LD90 = 0.47 mL/L were determined using the "probilog" computerized program. The regression equation was Y = 5.29 + 2.53 in X. Density, pH, liquid content and absorbance of the juice were determined. The stability of the A. legrelliana juice extract was compared using LD90 and it was observed that its effectiveness was reduced after long storage periods. The results attained were very encouraging since large volumes of water abounding in intermediate host mollusks can be treated with small quantities of juice at the same time that the toxicity which might be introduced by products of chemical origin is reduced.

[Shell identification of snail carriers of Fasciola hepatica in Cuba]. / Identificación conquiológica de moluscos hospederos de Fasciola hepatica en Cuba.

We show the main conchiological characteristics of Fossaria cubensis (Pfeiffer) and Pseudosuccinea columella (Say), intermediate hosts of Fasciola hepatica in Cuba. Also, their qualification is compared with the species which are confused.

[Population density of intermediary hosts of tropical diseases in watercress beds]. / Estudios de densidad de hospederos intermediarios de enfermedades tropicales en berreras.

A study of the density of river mollusks in six watercress groves is made. It is seen how densities of F. cubensis, intermediate host of fascioliasis in Cuba, is maintained with relative stability. The poor effectiveness of P. duryi as an agent of biologic control is demonstrated. The high density of P. cubensis, which seems to exert a certain regulatory effect on F. cubensis--particularly in the months of reproductive peaks (August and September)--is emphasized. Densities of B. havanensis and B. helophila may be affected by the density of F. cubensis and P. cubensis, which may exert certain influence in the decrease of pulmonate density. F. cubensis and P. parvulus are morphometrically compared and a high correlation between length and width of the shell (r = 0.9) is emphasized; such correlation was smaller in P. parvulus (r = 0.7).

[Influence of the aquatic vegetation on the distribution of river mollusks on the Isle of Youth]. / Influencia de la vegetación acuática en la distribución de los moluscos fluviales de la Isla de la Juventud.

A study is made in 24 bodies of water in the Isle of Youth, which are considered the most representative, since they include dams, lagoons, seasonal ponds, and marshes. The indicators of abundance and coverage of mollusks and plants, respectively, are determined. It was found that the first varies according to the second. Some vital functions of mollusks (nutrition, oviposition, and support substratum) are closely related to vegetation. It was found that P. paludosa inhabits bodies of water with T. domingensis, a plant used for oviposition and that pulmonates, on the other hand, require floating wide-leaved vegetation such as N. grayanum and N. advena. P. paludosa does not have strict requirements as regards the plants used in feeding, while planorbids require soft-leaved plants such as Chara sp., Cabomba sp., Lemma sp., and U. mixta.