74 MR WILLIAM TURNER AND DR H. S. WILSON ON THE 



Contrary to the opinions of Rathke and Claus, we find a very definite segmen- 

 tation of the body, indicated by constrictions on the margin and surfaces, l)y which 

 it is divided into as many portions as have already been described in the female 

 (fig. 12, 13). In the male the cephalic part preponderates in size greatly over 

 the thoracic and abdominal divisions. Connected to the head are a pair of 

 antennae, a pair of hooks, and three pairs of jaws, which, except in some slight 

 modifications of the antennae, closely resemble in their form, structure, and 

 arrangement, the corresponding parts in the female, though on a much smaller 

 scale. The thorax possesses neither dorsal nor ventral mesial processes, nor 

 lateral lappets. It is divided into four segments, the first and second of which 

 have, in connection with their ventral surface, two pairs of feet. These are 

 more simple than the thoracic feet of the female, and consist of truncated cones 

 with one or more papillae at their extremities. The abdominal segments ai'e 

 two in number — the proximal having in it the opening of the male genital 

 tube, the distal bearing two well-marked tapering papillae, as is the case in 

 the female. The alimentary canal lies in the axis. It has an oral opening in 

 front of the bases of the first pair of jaws, as in the female. The canal is dilated 

 anteriorly, and tapers somewhat posteriorly. It possesses no coeca. We could 

 not see an anus. We agree with Claus in the description which he gives 

 of the generative organs ; but from not having examined the male in the fresh 

 state, we did not observe the spindle-like spermatozoa which he describes. 

 Well marked bands of transversely striped muscular fibres are connected to the 

 jaws and other appendages, and, in addition, dorsal and ventral muscular bands 

 exist. 



Larva. — We have found the ova to present very different appearances in the 

 ova-strings of the different animals we have examined (fig. 15). In some the 

 germinal vesicle and spot were visible. In others the contents of the ova consisted 

 of closely-crowded opaque granules, due to segmentation of the yelk. In the more 

 advanced forms, which were distinguishable to the naked eye by the pinkish 

 colour of the strings, further stages in the development might be observed. In 

 some, a distinctly elongated body was contained, consisting of a mass of large 

 yelk granules. In others, a little more advanced, indications of limbs might be 

 seen, whilst at a still later stage the limbs and their divisions were clearly visible. 

 On various occasions we saw distinct movements, not only of the limbs, but of the 

 entire embryo within the ovum. When the embryo has reached this stage it 

 escapes from the ova-string, by a rupture of its thin wall, and of the outer covering 

 of the ovum ; the process being probably identical with that which has been 

 described and figured by Von Nobdmann,* in the Ergasilus Sieboldii. We have 



* Mikrographische Beitrage, 2d part, p. 13, PI. II., fig. 3. Berlin, 1832. 



