292 EXTEROPXEUSTA FROM THE SOUTH PACIFIC, 



TRUNK. 



All that need be said, and indeed in view of the fragmentary character of the 

 material, the most that can be said as to the peculiarities of the truncal region of 

 Pt. biminiensis, relates to points which have been already mentioned, namely, the 

 occurrence of ventral diverticula of the gill-pouches and the presence of accessory 

 gonads in the posterior branchial and genital regions. 



It is only necessary to add, with regard to the accessory gonads, that they do 

 not occur mediad of the main series, but only laterally, and they lie entirely within 

 the genital pleurae 1 . This is an important difference between this species and Pt. 

 aurantiaca where, as Spengel has shown, the accessory gonads occur both laterally 

 and medially, i.e., on both sides of the main series. In front the gonads commence 

 some distance behind the posterior rim of the collar. 



I think it has been made sufficiently clear that this is quite a distinct species. 

 Should the opportunity present itself to any naturalist visiting the Bahamas, particu- 

 larly the Bimini Lagoon, to make further observations, it is desirable to note the 

 external character of the genito-hepatic transition, the proportionate lengths of branchial 

 and genital regions and, in section, the nature of the pygochord, if one occurs. 



Pt. jamaicensis, n. sp. 



In the single specimen at my disposal, the proboscis was nearly concealed within 

 the collar-flap. The collar was much wrinkled and contracted to a length of about 



I cm.; the width was greater than the length in the contracted state. 



The width of the body in the branchial region, with closed genital pleurae, was 



II mm., and the vertical height, under the same conditions, was 17 mm. The width 

 across the expanded genital pleurae was 29 mm. This species therefore belongs to the 

 category of giant forms. 



Professor E. A. Andrews has kindly supplied me with notes as to the appearance 

 of this species during life together with some sketches, from which I gather the 

 following details. " Balanoglossus very abundant in sandy cove on north [side] of 

 Drunken Man Cay, off Harbour of Kingston." It lives in coral sand. " Only tail end 

 usually cut off by spade ; two $ heads taken in 3 — 4 hours." " Colour, yellowish 

 white, with conspicuous transverse bands of red-brown arranged alternately" on the 

 two sides of the body. 



On one side of the body (1 dorsal) these pigmented bands end sharply at the 

 sides of the median groove ; on the opposite side they bend forwards (or backwards) 

 and their ends break up into a number of spots on either side of the median line. 

 On the side on which the pigment-rows break up into spots, the body is "covered 

 by numerous rounded, blunt papillae [dermal islets] ; each [papilla] shows, under lens, 

 minute white specks," probably due to mucous glands. 



1 Of coarse this statement does not refer to the normal medial branch of the lateral gonads which always 

 occurs on the mesial side of the lateral septum. 



