ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 



there are four pairs of vesicular semiuales in the eighth to eleventh 

 segments. 



The origin of the paired vesicles has been investigated in L. tur- 

 gidtis. They do not, as Lankester supposed, arise as outgrowths from 

 the seminal funnels, but are developed quite independently of these. 

 They are formed as folds of the dissepiments, and the two anterior 

 project forwards, and the two posterior backwards. The appendages 

 of the median vesicle of L. terrestris arise in just the same way, but 

 it is not yet made out how this vesicle itself is formed. 



The receptaculum ovorum collects the ova until a sufficient num- 

 ber have been given off from the ovary to be laid. This was correctly 

 explained by Hering in L. turgidus. It has primitively no connection 

 with the oviduct or the funnels, but arises in just the same way as the 

 paired vesiculae seminales, with which it is completely homologous. 

 Later on, however, it becomes connected with the oviducal funnel. 



The receptacula seminis present variations in number and position, 

 and never appear till very late. They are primitively invaginations 

 of the epidermis of the intersegmental groove, but this invagination 

 merely gives rise to the epithelium of the receptacle. The peritoneum 

 forms their outer muscular layer, and they cannot be regarded as seg- 

 mental organs, as Lankester and others suppose. 



In a postscript the author gives an account of his examination of 

 two species of Perichseta. The testes and ovaries are in exactly the 

 same segments as in Lumbricus, but the former have undergone a 

 peculiar dislocation, for they are not now placed directly on the 

 hinder aspect of the special septa, but are removed from them, and, 

 with the seminal infundibula, lie enclosed in a capsule of connective 

 tissue. The testes have just the same structure as those of L. tur- 

 gidus. There are two pairs of vesiculas seminales (these have been 

 previously described as testes), which open into the capsule. The 

 ovaries are remarkable for consisting of a number of cylindrical 

 ovarian cords radiating from a common base ; as this allows of a 

 number of ova being given off at once there are no receptacula ovorum. 

 The oviducts open to the exterior by a common orifice on the 

 thirteenth segment. In one ('■ Horst's ") species there are four pairs, 

 and in the other two pairs of seminal pouches. 



Ovum of Clepsine and Gnathobdellidse-*— Dr. E. S. Bergh finds that 

 the ova of Clepsine are well adapted for embryological investigations, 

 owing to their large size and the ease with which they can be pre- 

 pared. He finds that the trunk-germs, and therefore the whole of the 

 trunk of the leech (with the exception of the midgut), arise from the 

 fourth larger cleavage sphere, while the cephalic germs are to be 

 referred to the smaller blastomeres. Each of these primary rudiments 

 is afterwards differentiated into ectoderm and mesoderm. The author 

 makes some criticisms on the results of Whitman and Nusbaum. 



Leeches of Japan, j — Dr. C. O. Whitman in his first paper on the 

 leeches of Japan, treats of the Hirudinidae or ten-eyed leeches. In 



* Zool. Anzeig., ix. (18S6) pp. 112-9. 



t Quart. Jouru. Micr. Sci., xxvi. (1886) pp. 317-ilG (5 pis.). 

 Ser. 2.— Vol. VI- 2 S 



