G76 ON DIPELTIS AND PROTOCARIS—SCHUCHERT. vol.xix. 



CLASSIFICATION. 



Family APODIDAE, Biirmeister (emend after Packard). 



" ilead and body iu front broad and flat, shovel-shaped or subquad- 

 rate; carapace broad and flat [usualljfollowedby a cylindrical body or 

 rarely by two lari^e thoracic segments]; the body cylindrical, few or 

 unmcrons segments extending beyond the carapace; antenna' small, 

 second pair minute, sometimes wanting; labrum large, broad, flat; feet 

 numerous, usually 63 pairs; with a large coxal, maxilla-like basal lobe 

 forming gnathites; beyond five subjointed endites; the 2-4 endites in 

 first pair of feet very long and slender, especially the fifth; gill pear- 

 shaped or bottle-shaped; flabellum triangular, simple; the fifth endite 

 of the first pair of legs is sometimes nearly as long as the body, the 

 eleventh pair l)earing e^g sacs, and in the male having the genital 

 outlet. Behind the eleventh pair two of the abdominal segments bear 

 each six pairs of appendages, there being many more appendages than 

 segments to the abdomen, while a variable number at the end are 

 without api)endages. Telson cylindrical, either short or ending (in 

 Lcpldnrus) in a long paddle-like outgrowth. A pair of [short or) long 

 filiform [or stout] jointed caudal appendages. Larva a nauplius." 

 Cambrian to llecent. 



^VPOmiSr^TC, new .snljlaiTiily. 



Characters of the family as given, omitting the two thoracic seg- 

 ments of the Dipeltiuie. Habitat: Marine and fresh waters. Cam- 

 brian to Keceut. 



Carapace subquadrangular. Protocaris. 



"Telson ending in a long paddle-shaped outgrowth. Lcj)idi(rt(s. 

 Telson short, cylindrical, simple. Apun^' (l*ackard). 



IDir'ELTi:?^.^, new sulDfainily. 



Like Apodin;e, but with a narrow head shield and two large, free, 

 thoracic segments. Telson apparently not diawn out. Ventral 

 appendages unknown. Habitat: Marine waters. Upper Carboniferous. 

 Dipdtis. 



EXPLANATION OF PLATE. 



Plate LVIII. 

 Proiocaris marshii, Walcott. 

 Fig. 1. Lower.Cambrian ; Swautou, Yt. Natural size. 

 Dipeltia diplodiscus, Packard. 



2. Lower Coal Measures; Morris, IlL View of the type specimen preserving 



tilts head shield, the first and portions of the second thoracic scgnitiits. 

 Natural size. Lacoe Collection. 



3. Specimen showing the complete h/'ad shield and the two large segments. 



Natural size. 

 4,5. Reverse and obverse, respectively, of a small, neiirly entire specimen. 

 Enlarged three times. 



Dipeltia carri, new species. 



6. Lower Coal Measures; Morris, 111. The central depression in this specLinen 

 is due to crushing. Enlarged three times. 



