MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Measurements (in millimeters), — Contiuued. 



351 



Sex. 



Length of cbela of tlio same 



(iroiitost bieuiltli of stiuio with spines . 

 (ircitcMt (li'pth of 8;iiius witlioiit spines 



Lenjith of dactyle of same 



Wiiith over tooth of dartylo 



Lenf;th of carpns of ri^ht tliinl pereiopod 



18 

 5 

 t 

 7 

 2 



i) 



fireatewt l)reailth of Name with spines . I 



(irealest l>reailtli of sauio without spines 3 



Length of nieros of saniu „. 12 



Length of foiirtli peieiopoil 'id 



Length ofdactylo of same l.f) 



Ldiigtli of piopodns of same 5 



Niiinber of riuj;.s in propodus 5 



Length of carpns of same 14 



Number of rings in carpns 12 



Length of meros of same.... 10 



Greatest breadth of meros 1.4 



Length of fifth peroiojiod 30 



Length of proijodns of same.. 5 



Number of rings in propodus '. 6 



Length of carpns of same 15 



Number of rings in carpus 13 



Length of meros of same 0.5 



Length of lirst pleopod 3 



Length of third jileopod 



Length of inner hiniella of same 4 



Breadth of inner lamella of same 1.5 



Length of outer lamella of same 4 



Length of inner Lamella of uropod 6.5 



Length of outer lamella of uropod - 7 



Greatest breadth of outer lamella of uropod 3 



Remarks. — The earliest figure of Stenopus liispitliis with which I am acquainted is that of 

 Olivier, published in ISll under the name of Palwmon hispidus (1, PL 19, Fig. 2). In this drawing 

 the third thoracic leg of the right side is represented as rudimentary. In explanation of this lie 

 says": "La pince gauche manquoit et paroissoit repousser. Dans uu autre, c'etoit Iadn)ite<iui 

 manquoit et paroissoit repousser de uieiue." The next drawing appears in Milne Edwards's Atlas 

 (3, PI. 25, Fig. 1.'}) of 1837. Like Olivier's plate this is crude and faulty. 



A second and very much better likeness of the Elispidus by Milne Edwards came out in 

 Cuvier's Le Rogne Animal (4, PL 50, Fig. 20). This is represented as pale straw (n)l<)r and was 

 evidently made from an old alcoholic specimen. Some of the parts are also figured. Adams's 

 figure (5, Tab. xii. Fig. 6), alreadj- noticed, and his brief description agree essentially with the 

 Nassau form. The antenuie are not in their natural position, and should probably be more 

 than twice as long as represented. Of the habits of the species ho says : " The Stenopus, Sicy- 

 ouia, and Pena'us, usually swim in a slow, deliberate manner forwards, and occasionally with 

 a sudden jerk propel themselves backward. They keep at a considerable distance from the shore 

 and seem to love deep still water, never ai)pcariug when the surface of the sea is riiftied." 

 The drawing by Dana (6, PL 40, Fig. 8) represents the antenna' of this animal for the first time 

 in a natural position. The antennal and antennular stalks are, however, much too slender, com- 

 pared either with Adams's figure or with the Nassau form. The length is given as 3 inches, while 

 the Steuoi)US on the plate measures about 2J inches. So far as it goes his description agrees in the 

 main with my own. He says: "The legs of the first and second pairs and of the fourth and fifth 

 are colorless, and they are extremely slender, much more so than in the drawings hitherto giving 

 of the Hispidus ; third pair is about one-fourth longer than body, fourth joint of .second pair nearly 

 twice as long as hand; fourth joint of fourth pair 12-joiuted, and fifth joint 7-joiuted; tarsus 

 minute (p. 600)." 



This extreme sleuderiiess does not appear in the specimens examined by me, nor is it apparent 

 in Adams's figure, which is one of the previous drawings referred to by Dana. In making the 

 drawing of the Nassau Stenopus (PL v) great pains were taken to represent all the appendages 



