34 MK. T. SCOTT 0\ ENTOMOSTEACA 



the 'Buccaneer' specimens, was, as already stated, 3"8 mm.; hut Semicalamis aculeatus, 

 Brady, measured 575 mm. in length — that is, fully half as long again as the ' Buccaneer ' 

 specimen. 



It is interesting to note that while six ^^ecxes of Memicalanus (including four of Claus's 

 Mediterranean species) have been obtained in the ' Buccaneer ' collection, only three 

 (including one of Claus's Mediterranean species) were observed in the collections of the 

 'Challenger' expedition, and further, that while Hemiealaiii were of frequent occurrence 

 in the ' Buccaneer ' tow-nettings, 85 perfect specimens, besides a number of others more or 

 less damaged, were captured in a single tow-net gathering. The three species recorded 

 in the ' Challenger ' Report were represented in the collection " only by about half a dozen 

 specimens in all." Such a remarkable difference in the distribution of the Memicalani 

 seems to indicate that their distribution is local, and that, with perhaps one or two 

 exceptions, they prefer to frequent what is comparatively inshore water to mid-ocean. 

 Hemic alcmus longicornis appears to be more cosmopolitan than the other species and to 

 have a more or less general distribution throughout tropical and subtropical seas. Yet, 

 though this SemiccdaiiHs has undoubtedly an extensive distribution, it is noteworthy 

 that none of Dana's species can be satisfactorily ascribed to it. This might have been 

 accounted for had it been a critical species, but the extremely long anterior antennse of 

 Hemicalanus longicornis at once distinguish it from all other Calmiidce. 



Genus Augaptilis, Giesbrecht (1889). 



Hemicalanus, Clans (in part). 



Augaptilis longicaudatus (Claus). (PL I. figs. 24-26; PL II. fig. 5.) 



1863. Hemicalanus longicaudatus, Claus, loc. cit. p. 179, pi. xxix. fig. 3. 



1892. Au(/aptilis longicornis, Giesbrecht, Fauna unci Flora des Golfes vonNeapel (Copepodeu), p. 414, 

 pi. 27. fig. 31 ; pi. 28. figs. 2, 8, 19, 23, 31, 3.5, 38; pi. 39. figs. 37, 48. 



Habitat. Station 3, 100 fathoms tow-netting, January 2nd (day collection). Lat. 1° 

 55' 5" N., long. 5° 55' 5" E., 360 fathoms tow-nettmg (day collection). 



This Augaptilis occurred only in the tow-nettings from the two localities described ; it 

 differs from other species of Hemicalanus in the great length of the secondary branch of 

 the posterior antennte, in the comparatively long caudal stylets, and particularly by 

 the anterior and posterior foot-jaws being furnished with moderately long setae, which 

 possess each a double row of short filaments with round, flat, button-like tops. These 

 filaments (or sense-organs ?) somewhat resemble " drawing-tacks," i. e. small nails 

 with round flat heads, used for fixing drawing-paper upon a drawing-board. There is a 

 double row of these filaments on each seta, the filaments of each double row being usually 

 opposite each other ; there are about 147 of these filaments in the length of a millimetre. 

 They impart to the setae that are furnished with them a very marked and striking 

 appearance. Prof. Claus considers them as forming an important and distinctive specific 

 character, and refers to them in his description of the species in the following terms : — 

 "Die Hakenhorsten der oberen imd untern Maxillarfiisse tragen zwei Reihen sehr zierlich 



