78 THE ATLANTIC. [chap. ii. 



position of the month, with its circle of branchiae, which was 

 placed on the lower surface of the body near the anterior ex- 

 tremity of the ambulatory area. 



The trawl contained unfortunately only a fragment of a very 

 large species of Balanoglossus. Although evidently a worm, 

 this animal presents so many anomalies in structure, that Ge- 

 genbaur has defined a distinct order in its class for its accommo- 

 dation, under the name of the Enteropneusta. The first known 

 sj)ecies, B. clavigerus, was originally discovered by Delle Chiage 

 in the Bay of Naples, and after his first description it remained 

 long unnoticed. Kowalewski subsequently detected another 

 species of the genus, B. luhiuhis, also in the Bay of Naples ; 

 and he worked out an excellent paper on the anatomy of the 

 genus, and showed that, like the Tunicata, Balanoglossus pos- 

 sessed a rudimentary branchial skeleton. 



The body, which is worm-like, is in three marked divisions ; 

 a stout muscular proboscis, with a terminal opening for the en- 

 trance and efiiux of water, round which there is a ring of rudi- 

 mentary eye-spots ; a strong muscular collar, somewhat like the 

 collar in Sahella or Clymejie, between which and the proboscis 

 the mouth is placed ; and the body, which is divided into three 

 regions — first, the branchial region, which occupies about one- 

 third of the length of the animal and in which the esophagus is 

 bordered by ranges of complicated gill-sacs, opening externally 

 and supported by a delicate skeleton ; secondly, a region which 

 contains a simple stomach with hepatic caeca and the reproduc- 

 tive organs ; and, thirdly, an enormously lengthened transpar- 

 ent gelatinous caudal region, terminated by the excretory open- 

 ing. In our specimen only the proboscis, the collar, and the 

 anterior portion of the branchial region were preserved ; but 

 the proportions of these — the proboscis alone 11 nnn. in length 

 by 18 mm. in width — proclaimed it a giant among its fellows. 



From its structure alone Balanoglossus claimed a special, we 

 might almost say a mysterious, interest ; for its unusual bran- 



