WEST INDIAN CENTIPEDES — CRABILL 193 



]-estricted to a small area of the outer surface of the 14th article, 

 but in Ityphilus idanus they occur on the outer as well as on the 

 inner surfaces of the 14th article. Their appearance and possibly 

 then* position suggest a chemoreceptive function. (3) Sensory points, 

 or sensilla, like the spatulate setae, occur in patches and quite con- 

 stantly (at least intraspecifically) in the same positions on the same 

 articles. These sensilla are distinctive in being very darkly colored, 

 very short and robust, and indistinctly or not at all alveolate. Ap- 

 parentl}' they have lost much or all of the mobility that is typical 

 of ordinary setae. I have observed such sensilla in many Geophilo- 

 morpha. Some of these points are probably responsive to environ- 

 mental stimuli, but the positions of others suggest a possible proprio- 

 ceptive role; that is, they may be positioned such that the movement 

 of one antennal article against another would stimulate them, and this 

 condition may well be concerned with suppljnng information pertinent 

 to the position in space of the whole antenna, or of individual articles, 

 or of groups of articles. 



Note F, A New Maxillary Character: "Bicondylic" is a new 

 term that I introduce in reference to the two condyles (one dorsal 

 and one ventral) whereby the basal telopodite article is articulated 

 with the second maxillary coxosternite. Evidently it has been over- 

 looked that though there are usually two such condyles, in some 

 genera there is only one. For instance, throughout the Holarctic 

 genus Arctogeophilus there is, to the best of my knowledge, never 

 more than one nodular condjde, the dorsal one, the ventral one 

 having degenerated and vanished completely. 



Note G, Geniculate Antenna: In alcohol the antenna is 

 distinctly geniculate, i.e., its distal group of swollen articles is bent 

 angularly to the axis of the series of more proximal fihform articles. 

 This condition is not evident in figure 8 because in Hoyer's mountant 

 an antenna tends to swell verj^ slightly and to straighten. 



Note H, Posterior Geminate Setae: In manj^ geopliilomorph 

 genera — including some quite distantly related and representing 

 different families — I have found a distinctive pah of cl3q3eal setae 

 to be of quite constant occurrence. Because these exhibit certain 

 special characteristics and should prove to be of systematic significance, 

 I term them specifically the posterior geminate setae. They always 

 occur as a pair on or close to the bod}" midline and usually some- 

 where on the posterior part of the clj'peus, often quite close to the 

 labrum. If they are homologous between gxoups, say from family 

 to family, then they are conceivably persistent and very primitive 

 structures. The alternative possibility, that they are only analogous 

 and have arisen independently many times, of course, is not easy to 

 discredit, especially since the geminate setae occur so widel}' and 



