462 



INVERTEBRATE MORPHOLOGY. 



however, possessing any ganglionic enlargement whicli can 

 be termed a cerebrum. Various nerves are given off from 

 the mass, two of which extend backwards throughout nearly 

 the entire length of the body. The only sense-organs pres- 

 ent are a number of small papillae on the anterior portion of 

 the body, which are probably tactile in function. 



Glandular organs are highly developed. Scattered over 

 the surface of the body are numerous flask-shaped glands, 

 apparently ectodermal in origin, while lying in the ccelom on 

 each side of the mid-gut and extending back almost to the 

 posterior end of the body are two long csecal tubes, a glan- 

 dular structure being also connected with them anteriorly. 

 These glands open in the vicinity of the hooks and have 

 hence been termed the hook-glands (Fig. 211, Tig), and it has 

 been suggested that they secrete a fluid which serves to keep 

 the blood which the parasite ingests from coagulating, being 

 thus similar to the glands in the pharynx of the Leeches 



ng IS 



Fig. 313. — Diagram op Stkucture of Fbmalb Pentastomum (after Spenbcb). 

 go = genital orifice. od = oviduct. 



hg = hooli-gland. ov = ovary. 



i = intestine. rs = seminal receptacle. 



ng = nerve-ganglion. ui = uterus. 



which serve the same purpose. Unless the ectodermal glands 

 are excretory, no special organs for the carrying on of that 

 function occur. 



The Peutastomidse are bisexual, the male being smaller 

 than the female, and recognizable by the situation of the geni- 

 tal orifice (Fig- 211, go), which is near the anterior end of the 

 body, while in the female it is near the posterior end. The 

 ovary and testis. are both unpaired organs situated beneath 

 the dorsal surface of the body and extending almost its entire 

 length. Anteriorly a pair of oviducts (Fig. 212, od) arise 

 from the extremity of the ovary (ov) and pass downwards and 



