CIO SUMMARY OF CURRENT RESEARCHES RELATING TO 



is larger ; the two ovaries lead into a vagina opening posteriorly, a 

 little in front of the anus. 



Count Tasserini describes (a) the structure of tlio ova, their 

 division into morulas, the formation of the gastrula by delamination, 

 the origin of the mesoderm from the proliferation of the endodcrm, 

 and the formation of the embryo within the egg-membrane. The 

 larval form differs from the adult in its relatively greater breadth, 

 in its sharply pointed tail, in the non-diiferentiation of the sex organs, 

 in the relatively longer pharynx, and the absence of the six oral 

 papilla). The body is well protected by a chitinous coat, and like 

 that of the adult, is striated, less distinctly anteriorly. The lateral 

 canals and their external aperture at the end of the pharynx, are 

 distinctly visible. 



The integument (b) consists (1) of a thin chitinous cuticle, con- 

 tinued inwards to line the pharynx, and perhaps further ; and (2) of a 

 delicate epidermis, in which the cellular structure could not be denned. 

 Both exhibit during life fino transverse striations, due to a sort of 

 permanent contraction of the subdermal muscles, (c) Below the 

 epidermis lies a layer of longitudinal muscles which have a spindle 

 shape, are drawn out at the ends, and exhibit distinct longitudinal 

 striations, and one or more nuclei. Frequently there is on the inner 

 face of the fibre a non-striated, protoplasmic portion, nucleated and 

 slightly granular. The various special muscles, those protruding 

 and retracting the penis, the ejac.ulatores of the testis, those associated 

 with the abdominal cirri, &c, are then described, (d) The muscular, 

 chitin-lined pharynx is suddenly constricted in front of the intestine, 

 in such a way that the return of food is impossible. The delicate 

 intestine, ending in a cloaca, into which the vasa deferentia also open, 

 is lined by a simple epithelium of large polygonal cells. No glands 

 were discovered. The contents consisted of pus globules with frag- 

 ments of lung parenchyma and tuberculous sarcoma, (c) The lateral 

 " excretory " canals originate in a deep caecum in the tail region, 

 and end similarly a little in front of the oral papillae. Where the 

 pharynx joins the intestine the two canals are united by fine ducts, 

 which unite and open externally. Further details as to contents, &c, 

 are communicated. (/) Multipolar cells, occurring at both ends of 

 the body, in connection with the papillse, cirri, &c, are described as 

 nervous elements. 



The male reproductive organs (#) are described at considerable 

 length. There is but one large testis, the other having probably 

 atrophied. A seminal duct connects the testis (which occupies a 

 large part of the body) with the penis. The testicular cells are at 

 first pyramidal, and exhibit a delicate apical " rachis," this is after- 

 wards lost, and the cells becoming free are modified into spherical 

 spermatozoa. The penis, which serves to keep the vas deferens in 

 connection with the vulva during copulation, consists of two elongated, 

 toothed, chitinous bodies {corpi copulatori), each of which is muscu- 

 larly connected with a terminal, recurved, toothed hook. The action 

 of the various muscles is noted. The six soft anal cirri also aid in 

 the copulatory act, embracing the posterior part of the body of the 



