76 



Prof. M'lntosli's Notes from the 



"The animal in qncstion was a female and a few ova were 

 observed seattered irregnlarly in the mesodermal tissne both 

 dorsal and ventral to the gnt. They were not regnlarly 

 arranged between tlie pockets of the gut, bnt possibly this may 

 have l)een due to the fact that sexual maturity does not oecur 

 in this species nntil several months after the date of the 

 capture of the abnormal specinien in January. 



"A slight irregularity may be noticed with regard to the 

 arrangement of the gut-pouches. In the normal Cerebratuhts 

 these correspond ou each side and are directed somewhat 

 anteriorly. Such was found to be tlie case in the anterior 

 j)ortion. 13eh)w the jioint of bifurcation, however, they 

 became iriegnlar in arrangement, and Avhilst those of the 

 outer sides of the two posterior parts were still directed 

 anteriorly, those of the inner sides were directed in the 

 o])i)osite direction (fig. 1). 



Fi-. 1. 



E. C. P. 



Gut-pouches at fork. 



'* Such being a brief description of the internal ariange- 

 nients, two points seem to call for special attention : — 



" Firstly, the fact that there are no neurochords in the third 

 nerve-cord does not agree with the only other ease in which 

 their behaviour in such an abnormality has been observed. 

 In a specimen of Lumbricidii s variegaius noted by Cori, each 

 of the three neurochords divided into two, one part going 

 to each posterior division. lint whereas Lumbriculus is 

 a Chaitopod with the nerve-cords closely apposed, in the 

 Isemertine they are Avidely separated. 



"The second point concerns the rhynchoccclom. As is 

 well known, this arises from a cleft appearing in the meso- 

 derm, M'hieh has grown round the unpaired ectodermal 

 invagination, which is destined to give rise to the epithelium 

 of the protruded proboscis. It seems a little remarkable 

 that, whilst that part which grows on to the unpaired ecto- 

 dermal invagination should remain single^ the portion of 



