406 
KATHLEEN HADDON, 
Aiiotliei’ interesting parallel is afforded by the Pedunculate 
Cirripede Anelasni a squalicola, which is parasitic on the 
Selachian genus Spinax. Gr. SinitlP describes this form as 
having a root system which arises from the region of fixation 
and penetrates into the flesh of the shark, probably serving to 
nourish the parasite, although the gut is not degenerate. The 
roots closely resemble those of Sacculina, having a chitiuous 
•investment, below which is a regular epithelium, while the 
inside is occupied by a lacunar tissue of vacuolated cells. This 
lacunar tissue is distributed over all parts of the body and 
may carry nonrishment, thus recalling a similar structure in 
Hei-pyllobius. 
Dr. Caiman has kindly drawn my attention to the fact that 
absorptive “roots” are also developed by some parasitic 
Isopods. Prof. Caullery* describes Wanalia as forming 
a tubular pi-olongation in the region of the mouth which 
penetrates into its host, Inachus, but it is at fii’st separated 
from the body cavity by a membrane. Two pairs of pro- 
cesses are then formed at the distal end, the mouth opens 
between them, and the whole system pierces through into the 
body cavity of the crab. This “ proboscis,” as Caullei-y calls 
it, serves the double purpose of fixation and of absorbing 
nourishment. A similar organ is found in the genus Crypto- 
niscus. 
We thus find a remarkable case of convergent evolution in 
the development of absorptive roots in the Copepoda, Cirri- 
pedia and Isopoda. 
YII. Systematic. 
Generic Characters of Herpy llobius. 
Female. — Body consistsof two parts joined by a stalk. The 
amterior part (root system), which lies within the host, is soft 
and elongated, composed of lacunar tissue, and provided 
' Smith, G., loc. cit. 
* Caullery, “ Rcclierches sur les Liriopsidse," ‘ Mittheiliuigen aus 
(lev Zool. Station zu Neapel,’ xviii, ltH)7-8, p. 583. 
