ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579 



commences the larva is uniformly covered with cilia ; the cephalic end 

 soon loses them, but becomes surrounded just in front of the mouth by a 

 strong prseoral ciliated band. The epiblast of the cephalic end 

 becomes thinner than the rest, except in the centre, where a group of 

 thicker cells remains to give rise to the cerebral ganglion. From the 

 broader anterior end of the pyriform embryo one or sometimes two long 

 and slender motionless flagella occasionally grow out ; the alimentary 

 canal becomes densely ciliated internally, and a few irregularly placed 

 cells are to be found between the epi- and hypoblast, which are probably 

 the foundations of the middle layer. 



In the course of the third day the praeoral circlet of cilia becomes 

 elevated on a distinct, slightly oblique ridge, and a reniform eye-spot 

 becomes developed at a little distance from the ganglion, with which it 

 is connected by a fibrous strand. A thin-walled vesicle which appears 

 at the hinder extremity of the body soon attains a considerable size ; it 

 is apparently formed by involution of the epiblast, and remains connected 

 with the exterior by a pore at the side of the anus. 



The larva of Eujpomatus is much smaller than that of Vermilia. 



Reproductive Organs of Phreoryctes.* — Mr. F. E. Beddard de- 

 scribes the reproductive organs of a new species o£ PJireoryctes from New 

 Zealand. There are two pairs of testes, which are large bodies, of, 

 apparently, an irregularly conical form ; an identical arrangement is 

 seen in Ocnerodrilus. There are two pairs of vasa deferentia, the funnela 

 of which are simple flattened discs, with an epithelium composed 

 of rather small, columnar, ciliated cells, so that they are not readily 

 found. All four vasa open independently, and there are no atria. So 

 far as is known this is a unique arrangement among the OligochEeta, 

 The simplicity of the efferent ducts in Phreoryctes suggests that they are 

 in a primitive condition. There are two pairs of ovaries, and as there 

 are two pairs of oviducts we may suppose that the peculiar possession of 

 the two pairs of ovaries is not an abnormal arrangement in this species. 

 Phreoryctes differs from all Oligochajta except Lumhricidus in the fact 

 that there are two pairs of oviducts opening on a line with the ventral 

 pair of setfe between segments 12 and 13, and segments 13 and 14. The 

 close agreement between the ducts as well as the glands of the male and 

 female reproductive systems in Phreoryctes is more apparent than in any 

 other Oligochsete, and is probably to be regarded as an indication of the 

 archaic condition of the reproductive system of this Annelid. 



Kleinenberg on Development of Lopadorhynelms.t — Mr. G. C. 

 Bourne calls attention to Prof. Kleinenberg's paper on the development 

 of Lopadorhynchus.X One important point on which Kleinenberg in- 

 sisted was that there is no such thing as a mesoblast as a specially 

 developed germ-layer. The mesoblast, so called, is in fact nothing more 

 than the aggregate of the primary, secondary, and tertiary tissues, the 

 precise origin of which is often obscured by the tendency to precocious 

 development. The study of Lopadorhynchus shows that the internal 

 organs of the adult Annelid are developed by successive differentiation 

 of derivates of the two primary layers, ectoderm and endoderm. This 

 Annelid has no mesoblast in the sense of a germ-layer composed of 



* Ann. and Mag. Nat. Hist., i. (1888) pp. 389-95 (1 pi.), 

 t Quart. Journ. Micr. Sci., xxviii. (1888) pp. 531-46. 

 X See this Journal, 1837, pp. 87-8. 



