WITH NOTES ON THE WEST INDIAN SPECIES. 289 



overpowering and very persistent even after years in alcohol. The Bahama [i.e. Bimini] 

 worm has quite a bearable stench, very much fainter." In section the difference of 

 the two species is at once evident. 



The species of the subgenus Tauroglossus may be arranged into two groups as 

 follows : — 



A. Gill-pouches with ventral coeca. 



Pt. clavigera, Pt. gigas, Pt. carnosa, Pt. biminiensis and Pt. jamaicensis. 



B. Gill-pouches without ventral coeca. 



Pt. aperta, Pt. australiensis and Pt. aurantiaca, 



or again according to the presence and absence of accessory gonads in the genital 

 region : — 



A. With accessory gonads in the posterior branchial and in the genital region. 

 Pt. aurantiaca, Pt. biminiensis and Pt. jamaicensis, Pt. carnosa (in old animals 1 ). 



B. Without accessory gonads. 



The remaining species named above, with the exception of Pt. gigas which must 

 be left doubtful in this respect. 



Pt. biminiensis, n. sp. 2 



The collar has a length of 10 mm. and the proboscis 375 mm. in two specimens. 

 The branchial region was much contracted and wrinkled measuring about 40 mm. in 

 length ; in the larger fragment about 24 mm. of the genital region remained. In 

 comparison with the following species the most useful measurement which I can state 

 is the width across the expanded genital pleurae, which did not exceed 12 mm. in 

 the alcoholic specimen. 



PROBOSCIS. 



Both this and the following species are without the special thickening of the 

 circular muscles at the base of the proboscis which is, according to Spengel, a 

 distinctive feature in Pt. clavigera. 



Stomochord. 



The region which has been referred to in the preceding pages as the coecal 

 dilatation of the stomochord is, in Pt. biminiensis, remarkable for its exceedingly 

 massive development. It recalls somewhat the condition met with in Pt. carnosa, 

 especially in regard to the occurrence of dorso-lateral pockets in connection with the 

 dorsal or main division of the lumen of the stomochord (cf. PI. XXIX. Fig. 17 a and 

 PI. XXXII. Fig. 65). The dorsal wall of the stomochord in the coecal region is 



1 The accessory genital ducts described above in old examples of Pt. carnosa do not necessarily and, 

 I think do not in fact, imply the independent origin of additional gonads. 



- For the habits of this species see the following :— T. H. Morgan, " The development of Balanoglossus," 

 Journ. Morph., Vol. ix. 1894, p. 1. 



40—2 



