352 GEOLOGICAL SURVEY OF THE TERRITORIES. 



its fellow of the opposite side when in repose). The two frontal ap- 

 pendages (PI. Xlir, figs. 4, 5) very long, coiled, and twisted, with 

 the a})pearance of being jointed, and gradually diminishing to a long, 

 curved point, which is minutely spinulated, the spinules short, stout 

 at base, and acute at tip ; variously and finely lobed with about seven 

 finger-like spinulated processes, best marked in old males (Fig. 22) ; near 



the middle a group of four 

 or five setae. These organs, 

 when stretched out, are 

 about three times as long 

 as the male claspers. As 

 a rule the 6th endites of 

 all the feet are narrow and 

 obtuse at the end, much as 

 in BrancMpus, the gill vary- 

 ing much in size. The 

 head of the female is sim- 

 ple, without any frontal ap- 

 pendages; the ovisac is 

 short and small, contain- 

 ing about a dozen very 

 large eggs, showing that 

 the number of individuals 



T-IG 22.-Chiro(vphaluaholmaui; male. Front view of head jj^ ^his SpCCiCS iS far IcSS 

 of male, much cnlavj;ta, the Iroulal appeudagts somewhat re- , • j-i j-i • ' ^ 



tracted; at>, hist antenna; at", second antenna or male clasper, tliau lU tUC Otlier SJ^CCICS 01 

 ■with the spur and filiform 2d joint ; fa, frontal appendage. Giss- fVip fn.inil V excent DPrhaDS 



Artemia. 



Total length of body of male, 15'"'"; of 2d antennse, 3™"'; of frontal 

 appendages when outstretched, 5-6"""; of genital organs, 2'"™; caudal 

 appendages, 2-2, 3""". 



Total length of female, 16™"; of ovisac, 2"™. 



I have received the <? and 9 from Mr. Eyder, the types of his descrip- 

 tion, and also a number of both sexes, the females with eggs, from Wood- 

 bury, ]Sr. J., near Philadelphia, collected in company Avith Branchipus 

 vernaliSj March 27, by Mr. William P. Seal; also from Glendale, Long 

 Island, from Dr. C. F. Gissler, who kindly sent me a drawing of the 

 head of an old male, although the sketches of the head of the male 

 by Mr. Eyder in the Proceedings of the Philadelphia Academj' of Sci- 

 ences are truthful to nature. 



This Branchipod is certainly, only excepting the next genus, the most 

 interesting and bizarre of all our fresh-water Phyllopods. The sketches 

 in Plate XIII will convey a better idea of the form of the feet than any 

 verbal description. 



Subfamily THAMNOCEPHALIN^E Packard. 



Body large, very stout and thick ; eleven pairs of feet ; 2d male an- 

 tennae with the 2d joint simple, curved; nine abdominal segments; ab- 

 domen broad and flat, ending in a single broad, spatulate, tin-like lobe; 

 endites of feet much broader and more rounded than in BrancMpodince ; 

 frontal appendage of male tree-like ; of female, long and clavate, simple. 



Thamnocephalus* Packard. 



Thamnocephahis Pack., Bull. Hayden's U. S. Geol. and Geogr. Survey Territories, iii, 

 175. April y, 1877. 



Male. — Claspers (second antennae) with the basal joint short, the upper 

 * SdjuvoZ, shrubby, busiiy ; KScpaXi, head. 



