250 BULLEXm OF THE 



PALLENOPSIS, gen. nor. 



Body slender, as in Phoxichilidium, segmented. Rostrum cylindrical Ab- 

 domen slender, simple. Antennae with lonr joints, large and chelate. Palpi 

 rudimentary, composed of a single joint. Accessory legs present in both sexes, 

 ten-jointed. Legs slender, dactylas with auxiliary claws. Two very unequal 

 pairs of large ocelli. 



This genus has the general appearance of a Pallene or Phoxichilidium. It is 

 however very distinct from them on account of the division of the basal joint 

 of the antennae into two, and in the different structure of the accessory legs ; 

 and it differs from all known genera in the existence of rudimentary palpi, 

 which are reduced to a single joint like the antenna3 of Tanystylum or Lecytho- 

 rhynchus. In all other genera, so far as I know, palpi are either quite absent or 

 fully developed (apparently serving as tactile organs); and their presence or ab- 

 sence is a convenient family character. Their structure in this genus shows of 

 how little value this character is, save as a matter of convenience. The genus 

 is exactly intermediate between the Nymphonidae and Pallenidae, as Sc(Borhxjn- 

 chus is intermediate between the former family and the Achelidae. 



The peculiar glandular duct near the middle of the fourth joints of the legs in 

 the nuile is perhaps a character of generic significance. It has not to my knowl- 

 edge been observed in any other Pycnogonid. 



Bohm has described and figured * a form from Patagonia which he identifies 

 with Kroyer's Phoxichilidium fluminense from Rio Janeiro, and which evi- 

 dently should be referred to Pallenopsis. Kroyer did not observe the rudi- 

 mentary palpi, but the close agreement in other characters leaves little reason 

 to doubt the correctness of Bohm's identification. Neither Kroyer nor Bohm 

 mentions the extra joint of the antenna, though the latter observed a " char- 

 akteristischen durch eine Linie stiirkerer Haare markirten Knick," near the 

 middle of the basal joint. There can be no doubt of the presence of a distinct 

 articulation at this point in our specimens. The species described below are 

 very distinct from Kroyer's species ; the most striking difference is the much 

 smaller size of the auxiliary claws in the former, and the non-plumose character 

 of the hairs on the ambulatory legs. 



Pallenopsis forficifer, sp. nov. 



Flates IV. and V. 



Body (Fig. 15) comparatively stout, distinctly segmented. Lateral processes 

 very distinct and prominent, slightly longer than the width of the body, sepa- 

 rated by intervals less than their own width. The anterior pair are directed 

 somewhat forwards and upwards, the posterior i)air obliquely backwards like 

 the branches of a V. 



• Monatsbericht der Koniglich Preussischen Akademie der Wissenschaften zu 

 Berlin, Februar, 1879, p. 180, Tafel I. Fig. 4. 



