374 SUMMARY OF CURRENT RESEARCHES RELATING TO 



spermatozoa are more abundant than are ova. The pouch which Cuvier 

 took for a bladder appears to be not a spermatic reservoir, but a store- 

 place for reserve elements which do not escape at the same time as the 

 ejaculated mass of spermatozoa. 



In answer to these remarks M. E. Saint-Loup * urges that at one 

 period the hermaphrodite gland elaborates male elements, and that such 

 individuals may, for the time, be regarded as males ; at other times it 

 produces both male and female elements without either predominating, 

 and lastly the female elements distinctly predominate. In all these 

 stages the individuals are fit for copulation. 



Genera of .ffiolidiidse.f — Dr. E. Bergh continues his investigations on 

 Nudibranchs in a systematic account of the iEolidiidsB, accompanied by 

 five plates. The genus ^oUdiella, with JE. orientalis sp. n. ; Glaucus, 

 with Gl. atlanticus Forst. ; Hervia, with H. rosea sp. n. ; Moridilla g. n., 

 with M. hrocMi sp. n. ; Cerherilla, with G. annulata (Quoy et Gaim.) var., 

 affinis Bgh. ; Melibe Eang, with M. ocellata sp. n. ; Doto, with Doto 

 fragilis Forbes ; Hero Loven, with H. formosa Loven, are described and 

 figured. 



The new genus Moridilla is thus diagnosed : — Body slender, elongated, 

 subcompressed ; rhinophoria somewhat mulberry-like ; tentacles long ; 

 dorsal papillae not readily caducous, elongated, disposed in oblique rows, 

 anteriorly in groups ; foot rather narrow, with the anterior angles pro- 

 duced like tentacles; mandibles moderately long; masticatory process 

 not curved, with a single series of coarse denticles ; lingual teeth in a 

 single row, almost as in Facellinse ; penis unarmed. 



New Genus of Parasitic Mollusca.| — Mr. E. A. Smith forms the 

 new genus Bohillardia on a single specimen of a shell which was stated to 

 have been found living on an Echinus. In the absence of the animal it 

 is impossible to assign this new form to any definite systematic position, 

 but the delicate shell is stated to have the glassy texture of Carinaria, 

 and somewhat the form of a certain species of Hyalina ; it appears to bo 

 viviparous. The shell of iJ. cernica has a longer diameter of 8, and a 

 shorter diameter of 6 • 5 mm., with a height of 5 mm. Mr. Smith takes 

 the opportunity of collecting in a very convenient form the names and 

 habitats of most of the already described parasitic genera of Mollusca. 



5, Lamellibranchiata. 



Abdominal Sensory Organs in Lamellibranchiata.§ — Dr. J. Thiele 

 gives a full account of the sensory organs discovered by him in certain 

 Lamellibranchs, the preliminary account of which we have already 

 noticed. II It is now noted that in several genera the sensory body on 

 the left side is degenerate, or, as in Pecten and Ostrea, wanting. The 

 search for these organs in the siphoniate forms has remained vain. 

 The only organs in other Molluscs which can in any way be compared 

 to them are the sensory structures found near the gill of Nautilus, but 

 this even is doubtful. 



The extraordinary resemblance between the epithelium of these 



* Comptes Eendu8, cviii. (1889) pp. 364-5. 



t Verb. K. K. Zool.-Bot. Gesell., xxxviii. (1888) pp. 673-706 (5 pis.), 



X Ann. and Mag. Nat. Hist., iii. (1889) pp. 270-1. 



§ Zeitschr. f. Wiss. Zool., xlviii. (1889) pp. 47-59 (1 pL), 



II This Journal, 1888, p. 942. 



