Mr Harmer, Note on the name Balanoglossus. 191 



included. It appears, however, from Willey's researches 1 that 

 Pt. flava belongs to the genus (or sub-genus) Chlamydothorax 

 a conclusion previously suspected by Spengel. 



The name Balanoglossus is retained by Spengel (p. 350) for a 

 group of species including B. kupfferi and B. kowalevskii, largely 

 on the ground " dass die Gattung Balanoglossus in diesem Sinne 

 die primitivsten Formen umfasst, denen auf diese Weise der 

 altbekannte Name gewahrt bleibt." 



Although feeling great reluctance to suggest changes in the 

 nomenclature of the Enteropneusta, I am induced to do so by 

 having found considerable inconvenience in using Spengel's 

 terminology, which does not appear to be in accordance with 

 recognised rules. Balanoglossus is clearly a synonym of Ptycho- 

 dera; and although Spengel might have been justified in rejecting 

 the older name on the ground that Balanoglossus had been 

 universally accepted by Zoologists for more than half a century, it 

 would be difficult to maintain this position since the appearance 

 of Spengel's great monograph and the adhesion to his nomenclature 

 of Willey and other recent writers. Balanoglossus ought, there- 

 fore, to disappear as a genus. I think that the restricted sense in 

 which Spengel uses it is unfortunate, since the type-species (Delle 

 Chiaje) is thereby excluded from the genus to which it properly 

 belongs. Spengel's contention that the species placed by him in 

 that genus are the most primitive of Enteropneusta is expressly 

 controverted by Willey, and whatever conclusion (if any) might 

 be derived from that argument thus loses its force. 



The disappearance of the familiar name Balanoglossus would 

 be a matter for regret ; but I think that it may conveniently be 

 retained as a semi-popular name for any species of Enteropneusta ; 

 — a practice which is commonly adopted in Zoological works. In 

 order to facilitate its use in this way I suggest the new generic 

 name Balanocephalus to include the species which are at present 

 placed in Spengel's restricted genus Balanoglossus. The earliest 

 described species belonging to this group is B. kupfferi, v. Willemoes 

 Suhm, which would accordingly be the type-species. Spengel's 

 sub-genus Dolichoglossus (p. 360) cannot well be accepted instead 

 of Balanocephalus, as it is expressly restricted by him to the 

 species (B. kotualevskii etc.) with a long proboscis, and would be 

 misleading if applied to the other species. If it is desirable, as 

 Spengel suggests, to subdivide the genus Ptychodera, the application 

 of the strict laws of nomenclature would necessitate the use of that 

 name for the Ghlamydothorax-grow^, and the introduction of a new 

 generic name for Pt. minuta and Pt. sarniensis. 



1 Quart. J. Micr. Sci., xl., 1898, p. 165, and Zool. Results, Part III., 1899, 

 p. 227. 



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