Entozoa of Brit Uh Marine Fiahes. 9 



long ; greatest breadtli half the length. Oral sucker "21 mm. 

 in diumefer ; ventral suckt^r '32 x 'iM mm., situated •.'),') mm. 

 from the antt-rior eiul. Pliaryiix 'ItX'llinm., prepharyiix 

 anil (Bso|)hai;U3 short. Ovary oval, immivliat'ly behind the 

 vential sucker on the ri;;ht side, smaller than the testes. 

 Testes imnu'diatrly boh hid ovary, tandem. Yolk-glands not 

 very voluminous, lateral, extending into neck as tar as in- 

 testinal bifurcation ; almost absent at level of ventral sucker; 

 uniting bt-hind testes. Gorntal aperture median, not far in 

 front of vential sucker. Cirrus-pouch short, not cxtcndinj^ 

 beyond the centre of the vintral sucker, containing a simple 

 vesicula seminalis, a short ductus cjactulatorius, and aj)pa- 

 rently a definite pars prostatica. Ova -OS-i-OSG x •040-042 

 mm. ; blunt at both poles. Simple excretory vesicle ex- 

 tending forward to anterior testis. 



Mr. Johnstone, of Liverpool, has allowed me to examine a 

 small immature specimen of what appears to be the same 

 species from Callionymns (yra, obtained in Luce Bay. I have 

 also collected a considerable number of specimens from 

 Callioitymus in the Firth of Clyde. These appear to be the 

 same species ; a description of them will be published later. 



Tiiis specimen agrees with Looss's description of Disto- 

 tnum alacre in several important j articulars. The disposition 

 of the genital orgaiis is the same in both, although the yolk- 

 glands are not so extensive in my specimen. They agree 

 also in the size and situation of the ventral sucker. Tlie 

 most important differences are that my specimen is much 

 broader, while the oral sucker and pharynx are much larger. 

 In these respects it approaches nearer Lebouria idonea, 

 mihi *. 



Looss seemed to hesitate in including Distomum alacre 

 amongst the Allocreadiina?, but there seems little doubt that 

 it is really a member of this subfamily. It is most nearly 

 related to the genus Lebouria, and it is oidy tlie somewhat 

 anomalous structure of the cirrus-pouch which prevents its 

 definite inclusion in that genus. 



In the specimens from tlie West Coast the average length 

 is 1*1 mm., the breadth is § of that, and the ventral sucker 

 is situated exactly § of the length from the anterior end. 

 The diameter of the oral sucker is constantly ^ of tlie body- 

 length, while that of the ventral sucker is a tiifle more than 

 ^. 'i'lie ventral sucker is oval and its shorter diameter is not 

 quite I of the body-length. The pharynx is exactly -j^j of 

 the body-length. In practically every one of these features 



• Quart. J. Micr. Sci. liii. pt. 3, pp. 4-11-461, pi. ix. fig". 9-12. 



