THE ATTACHED YOUNG OF THE CRAYFISH CAM- 

 BARUS CLARKII AND CAMBARUS DIOGENES 



E. A. ANDREWS. 



A REMARKABLE fact in the life history of the crayfish is that the 

 young associiate with the mother for many days after leaving the 

 egg, being at first firmly fastened to her and later going back to her 

 for protection until finally quite independent. 



As pointed out in The American Naiuralist, :\rarch, 1904, 

 Cambarus affinis molts twice while fast to the mother and leaves 

 her only in the third stage. Some facts as to the character of this 

 incipient family life in an American Astacus from Oregon will be 

 given in another communication. The object of the present note 

 is to describe the association of parent and offspring in two more 

 species of Cambarus and to compare this with what is found in 

 C. ajfinis and in Astacus. The illustrations are all of ('. darkii. 



The young of C. clarkii were obtained from eggs laid in con- 

 finement by adults shipped from New Orleans, November IS, 

 1904; some 18 out of 61 surviving the journey. Two of these 

 active, prawn-like and brilliant red crayfish, one male and one 

 female lived in a shallow sink of warmish water during the 

 w^inter and by ]\Iarch 25, 1905, the single female lunl the abdominal 

 basket full of many very small and vt>ry dark-colored eggs. These 

 eggs were already in the stage H of ReicluMil)acli but differed from 

 that in having the abdomen larger. Facli egg was about 1\ mm. 

 in diameter and partook of the exceptionally vivid coloring of tiie 

 adult, the large oil-like yolk drops being wine colored instead of 

 yellow as in Cambarus ajjiiii.s. 



When re<-eived in November, tlnvc of the fctnalo examined 

 had only minute yellow eggs in tlie ovaries and no s,>crni in the 

 ainnili. while the males had small testes but yet mature .perm in 

 the va>a defcirntia. It would thus appear that the seas.m of 



earh- spring, l.u't thi.-> can be deteriuiued onlv l.v (.bservations in 

 thefiehl. 



