Kiiiozoa ('/ British Marine Fi's/ief. 13 



escnpctl notice, for tlicy arc prominent ami distinct enough in 

 the spccinuMia in wliicli tlioy arc present. I'lio sanio a|»plie» 

 to the ventral series of very small 8j)ine.«, which Looss 

 describes as consisting of two rows of 5 and (3 in each. In 

 some of my specimens these are entirely absent, and in the 

 others they vary in number from 3 up to 15. In the speci- 

 men in which tho maximum number was present tliere were 

 6 spines in the anterior ruw and 7 in the posterior row, and 

 at each end of the series there was a 8in;;le spino of tho same 

 size occupyinnr a position neither in one row nor the other, 

 but midway between the two. From this it is evident that 

 it is a difficult matter to determine the exact number of the 

 ventral series, and there may ovtn be a doubt if it consists 

 normally of a definite number. The arrangement of the 

 largest spines is exactly as Looss !ias described, the spines 

 being all of approximately equal length ("O-I-'Oa mm.) except 

 the two terminal spines of the anterior row, which are a little 

 shorter than the others. I find the number to be 18 in the 

 anterior row and 17 in the posterior, but it is not easy to 

 determine this exactly. 



Tiio oral sucker is terminal and measures '19— "22 mm. in 

 diameter, »'. e. about j^^ of the body-length. It has a slight 

 tendency towards a funnel-shape, but the margin is not 

 necessarily rampart-like (wallartig) as Looss describes it. 

 In almost all my specimens the ventral lip is thin and sharp, 

 while the dorsal lip is thickened for the insertion of the 

 large cephalic spines. Along with the spines this thickening 

 extends round to the sides, and tiiis gives the head a some- 

 what square sliape in some specimens. The ventral sucker is 

 situated at a distance from the anterior end varying with the 

 degree of extension of the neck, but on an average it is about 

 1 mm.; in other words, the sucker lies a little in front of the 

 middle of the body. It is a feeble, shallow, evidently 

 degenerate structure. In most cases it lies level with the 

 body-surface, but in some its edges are raised a little. It is 

 always distinctly larger than the oral sucker, its diameter 

 being •22-*27 mm., and the sucker-ratio being approxi- 

 mately 6 : 7. 



The prepharynx is about '1 ram. in length, but may be 

 twice as long or entirely absent, according to the state of 

 contraction. The pharynx h^is an average measuremont of 

 "145 X "10 mm. The oesophagus is norn)ally a trifle shorter 

 than the pharynx. The diverticula are thin-walled and wide, 

 extending quite to the posterior end of the body. 



The ovary and testes are situated in the posterior half of 

 the body, the post-testicular space being a little more than f 



