i6 



Jaws slender, moderately curved, acutely pointed by delicate short tips. Anterior teeth with 

 broad bases, rather short. Posterior teeth slender, sharp, closely set below, diverging distally. 



Vestibular ridge high, with numerous, fairly regular, papillae. Corona ciliata fairly long, 

 extending up to or just on to the head, but not reaching to between the eyes; otherwise like 

 that of bipunctata; extending for a half or two-thirds of the distance between head and ganglion. 

 Formulae: — 



o.o 



3° 



7 



6-7 



14—15 



9-5 



31 



7 



7 



15 



8.0 



30—37 



6-7 



4-6 



9—14 



7-5 



26-33 



6-7 



4—5 



10—13 



7.0 



26-35 



6-7 



4-6 



9 — 1 2 



6-5 



30 



6-7 



4—5 



9 — 10 



6.0 



33 



5—8 



3 — 5 



9— 11 



5-5 



3 —36 



6 



4 



10 — 1 1 



5-o 



30—40 



6-7 



3—4 



7—10 



This species resembles Aida's regularis so closely on paper, that for some time I 

 suspected them of being synonymous; it is therefore worth while to enter into the differences 

 between them in some detail. 



Neither neglecta nor regularis have been fully described, and Aida's two figures of 

 regularis (woodcut 1 and fig. 8) do not agree with one another in the proportional length of 

 corona and tail-segment. Still, accepting these figures, and adding to them the features of the 

 Siboga specimens, we may say that the main points of difference are that in neglecta the tail 

 is slightly shorter, the posterior fin reaches further in front of the septum, the corona ciliata is 

 slightly longer; and (what is well brought out in Doncaster's figure of regularis) that the slight 

 epidermic thickening or collarette in neglecta is very much more developed in regularis both in 

 length and breadth. The numbers of both anterior and posterior teeth are greater in neglecta. 



At first sight the Siboga specimens seemed to link the two species; they agreed with 

 neglecta in the number of anterior and posterior teeth, and in the length of the corona; they 

 better agreed with regularis in the number of jaws, in the extension of the posterior fin, and 

 in the proportion of the tail segment. They further agreed with regularis in a point on which 

 A ida laid great stress, namely,' the regularity of the tactile prominences; a comparison of his 

 figure A. (Op. cit., p. 17) with my figure 44 will show that these are practically identical, 

 spot for spot. At the same time I think that he exaggerates the importance of this character, 

 which is equally well exhibited by many other species, as for instance by bipunctata (compare 

 Grassi's figure, pi. IX, fig. 2). But eventually the two species fell naturally apart, although 

 showing greater variation of the armature than Aida's statement suggested, notably as regards 

 the number of jaws. 



I must withdraw the suggestion made in the Biscayan Report (p. 72, note to table) 

 that neglecta was "almost certainly bipunctata". At the same time they are most annoyingly 

 like one another, and are not easily distinguishable except in well preserved material. The 



