ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 457 



Contrary to the opinion of Quatrefages, tlie author believes that the 

 first cleavage-groove always has a relation to the position of the globules 

 in question, and that it does not appear at an indefinite point. An 

 amphiblastula is formed. Twelve hours after fecundation the embryo 

 has the form of a mesotrochal larva, with a group of long cilia at the 

 cephalic pole. After four days the larva is cupola-shaped, owin^ to 

 the great development of the pre-oral portion ; the cesophagus is 

 lined by vibratile cilia, and the anus is terminal ; there is a groove 

 on the ventral surface, four temporary setae on either side, and two 

 small brown eye-spots. 



Anatomy of Sternaspis scutata.* — M. Max Eietsch describes 

 some points in the structure of this Gephyrean. 



After a general description of the external characters, he shows 

 that the integumentary layer consists of a thick and resistent fibrous 

 portion, striated parallel to the surface, and invested by a layer of 

 setae which alone appear to represent the epidermis, and lined inter- 

 nally by a granular layer, in which nuclei can sometimes be detected ; 

 from this there are given off a number of filaments, which pass into 

 the seta3 and appear to represent the terminations of nerves. 



The muscles which cause the invagination of the anterior portion 

 of the body are highly developed ; the digestive tract forms a number 

 of folds, and coils spirally around the generative organs ; there is a 

 wide, short, and protractile pharynx, with glandular projections, a 

 narrower and longer oesophagus, analogous in its structure to the 

 stomach, but distinguished from it by the absence of a vibratile canal 

 and by the non-granular character of its epithelial layer ; the stomach 

 is the largest portion of the intestine, and its glandular epithelium is 

 highly developed and gives rise to a number of internally projecting, 

 longitudinal elevations ; the secretion appears to be biliary in cha- 

 racter. The nervous system is composed of two cerebral ganglia, a 

 wide collar, and a ventral cord which is enlarged at one point owing 

 to the great development of its connective tissue. The branchial 

 filaments have no cilia, and their internal cavity is divided longitudi- 

 nally by a fibro-muscular partition ; the two sinuses thus formed 

 communicate at either extremity ; the blood, being coloured red, is 

 easily seen in its passage through them. An account of the other 

 organs is reserved. 



Entozoic Vermes.f — Dr. E. Moniez mentions but does not describe 

 a large Spiroptera which he found under the mucous membrane of 

 the stomach of the rabbit, and for which he jiroj^oses the name of 

 S, leporum. In the mole the same author has found Tcenia Barroisii 

 n. sp., which is distinguished from T. bacillaris by its greater size and 

 thickness, while the rings are shorter, and the ova without appendages 

 and smaller than in the form just named. 



Dr. Moniez also points out that in Ahotlirium gadi the vessels 

 contain a spiral tube, which is distinct from their walls and can be 

 unrolled like a trachea. 



* Comptes Kendus, xcii. (1881) pp. 926-9. 



t Bull. Sci. De'p. du Nord, iii. (1880) pp. 447-8. 



