582 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



mouth, l)ut novor, to tlie author's knowledge, wltliin the t^ill covers. 

 They are not as active as iui/><i.i\ hut upon occasion can move ahout 

 with equal speed and facility. They live but a short time after being- 

 taken from their host since they exhibit to a marked degree the per- 

 nicious habit of crawling up out of the water and remaining there 

 until dead. They are also very susceptible to a slight rise in tempera- 

 ture; Pickering and Dana say (p. 67) that " when the temperature 

 has been as high as (JO F., they have generall}' died in the course of 

 a short time.'' The author's experience has been similar, although no 

 actual temperature tests have been made. 



Being susceptible to so slight a rise it becomes extremely difficult 

 to handle them during the sunnner months, when most of the research 

 work is being done at the Marine Biological Laboratories. It is not 

 surprising, therefore, that so little has been ascertained in regard to 

 their habits and development, even though they are so common. 



The Museum collection includes the following: 



From the codfish {Gaditx morliua) of Woods Hole and the imme- 

 diate vicinity four lots numbered lUilS, and one each 12305,12649, 

 12650, Ace. no. 19898, and the following collected by Vinal N. 

 Edwards, 1301, 1384, 1393, 1417, 1423, 1463, 1466, 1485. * These lots 

 include something like 250 specimens. From codfish off the coast of 

 Maine, chiefly near Casco Bay, lots 8022, 8023, 8024, 8025, 12646, 

 12653, 12654, 12655, 12660, 12661, 12907, nearly 200 specimens more. 

 From codfish in Massachusetts Bay lots 12656, 12657, 12658. From 

 other localities, chiefly stations of the U. S. Bureau of Fisheries vessels 

 AlhcUross and Oiroiqmx, lots 16644, 12645, 12647, 12648, 12671, 12672, 

 12673, and W. 31. From the haddock {3felan<>(/rammus fegle/inm) 

 lots 12307, 12651, 12659, W. 25, W. 26, W. 41. From the hake 

 ( Uroj>/u/ri.s tenuis) lots 8026, 13203, W. 30. From the halil)ut {IJIppo- 

 gloKSKK Jitppoglossus) 12631. From the pollack (Poilae/u'us virens) 

 W. 27, W. 28, W. 29. From the ])arn door skate {Raia Ise'vis) 858, 

 6162. From the surface 12908 and W. 32. Specimens of the chali- 

 mus of this species are included in lots W. 36 from the tomcod; W. 37 

 host unknown, and 8116 from fin of codfish. 



CALIGUS CHELIFER, new species. 

 Plate XI. 



Female. — Carapace ovate, a sixth to a cpiarter longer than wide, con- 

 siderably narrowed anteriorly. Frontal plates well defined; lunules 

 large, close together, nearly circular, and prominent (fig. 126). 



Posterior sinuses Avide and nearly parallel; median l()])e half the 

 entire width, projecting consideral)ly, and contracted into a narrow 

 neck where it joins the free segment. 



Tiioracic area two-thirds the width and one-half the length of the 

 carapace, suluiuadrilatiM-al. Free th(uax segment very shoi't, a little 



