ON THE CIIILOPODA OF NORTH AMERICA. 9 



tubercles or -pines. Their border is everted) and generally crenalate ami spinous. 

 Tin' legs are very long and serrated by parallel rows of spinulaa. They are also 

 furnished with rings, of long -lender spines, encircling the joints. Thesideshave nine 

 pairs of spiracles, — the openings into the tracheal vessels. The anal segment in the 

 female is elongate, and the external organs of generation are furnished with a pair of 

 forceps, replaced in the male by a pair of styliform appendages. The sterna (fifteen 

 in number) are small. It is very evident that the number of segments is fifteen, and 

 that each scutum, except the last, is formed ly the coalition of two neighboring ones. 

 The pattern of coloration is peculiar to this family ; it consists of longitudinal stripes 

 on the body and annuli en the appendages, (liven predominates. There has 

 as yet only one genus been found in this family, among which so great a unifor- 

 mity exists as to make the distinguishing of species a, task of considerable difficulty. 



The color is probably a good specific character, but is seldom, if ever, preserved. 

 We have seen specimens of S. forceps changed almost immediately to green or blue, 

 or, more commonly, brighl purple, by alcohol. 



All our descriptions of new species are drawn up from alcoholic specimens, and 

 therefore proper allowance should be made in estimating their accuracy as regards 

 Coloration. 



Any anatomical characters are very obscure ; but Mr. Newport considers the pro- 

 portionate lengths of the metatarsal joints as constant, and we have found them so, as 

 far as our limited observations have gone. 



The lengths of the antennas and posterior pair of legs, as compared with the body, 

 are also probably good characters, hut very liable to misinterpretation; for it is dilli- 

 cnlt. often impossible, to tell when the former are broken and when the latter are 

 imperfect, reproduced, appendages. Mr. Templeton, who first suggested these points, 

 al-o makes use of the si/.e of the marginal spines of the scuta in his descriptions. The 

 peculiarities of the surface of the scuta also appear to be good secondary characters. 



Gen. 1. CERMATIA, UUger. 



ut magnum. Oculi prominentia. Stomata dorsalia lateribus incrassata. 

 t, Lamarck, Anim. Sana \ i rtb. 

 Rafinesque, Annals of Nature. 



C. forceps. — C. viridi-brunnea, fasciis tribus longitudinalibus saturate viridibus; capite dense minute 

 punctato, anticc breviter piloso, et linea depressa lonu'ituJinale mediana et ante oeulum utrinque altera 

 curvata, et altera tranversa inter oeulos, et postice depressione lata insculpto; antennis mandibulisque 

 ferrugineis; scutis dense minute puuetatis, spinulis nunierosis aspcratis, valde imbrieatis, angulis ro- 

 tundatis, marginibua elevatis sed tenuibus et "spinis quam in Ccrm. coleoptrata evidentioribus;" 

 lateribus plerumque rufescenti tinctis; femoribus singulo auuulo unico saturate viridi ; tibiis et tarsia 

 biannulatis; pedum pari postremo in mare corpore vix \ longiore (in femina bis longiore ;) articulo 



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