500 W. BLAXLAND BENHAM. 



So much for its generic characters. There is no doubt that 

 it belongs to the genus Balanoglossus. With regard to 

 specific characters, it belongs to the same section of the genus 

 as B. Kowalevskii and B. Mereschkovskii, as is shown 

 by the following features : — The great relative length of the 

 proboscis; indeed, this length is greater in B. otagoensis than 

 in either of these; there is only a single proboscis pore; there 

 are no median gonads. Further, it possesses paired intestino- 

 tegumentary canals (Darmpforte of Spengel), as do these two 

 species ; but whilst in them there is at least six pairs of these 

 peculiar structures, there is but a single pair in B. otago- 

 ensis (as in the genus Schizocardium). It may not be 

 quite safe, perhaps, to place much reliance on this point from 

 an examination of so few specimens, since Spengel states that 

 the number is not constant in B. Kowalevskii, and suggests 

 that it increases with age, as do the gills and gonads. Never- 

 theless it seems to me probable that a single pair is constant 

 in B. otagoensis from the following fact: not only is there 

 only a single pair observable in the sections of the adult 

 animal, but in the smaller younger specimens, in which no 

 gonads are as yet developed, the canals are already present, 

 although the gill-slits have not reached more than half their 

 total number; the canals, then, appear early in life. 



Another distinction of specific importance is noticeable in 

 the sections, in regard to the longitudinal muscles of the pro- 

 boscis. In both the species referred to above, Spengel de- 

 scribes the muscles as being arranged in several concentric 

 layers, encroaching considerably on the connective tissue 

 which more or less fills the proboscis. In B. otagoensis, 

 however, the longitudinal muscles of this organ are confined 

 to a very narrow band (fig. 5, d), close to the circular muscles, 

 which, as in Balanoglossus generally, are very feebly de- 

 veloped. 



From these facts there is no doubt but that the New Zea- 

 land species is quite distinct from the American and European 

 species. But there is a Japanese species, briefly described by 

 Spengel, which agrees with B. otagoensis in the most 



