406 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



tion: Circumtropical, in some regions reaching 

 Arctic or Antarctic waters. From less than 200 

 to more than 1,000 fathoms. The Museum of 

 Comparative Zoology has one record from the 

 Gulf of Mexico at about 28° latitude and 87° lon- 

 gitude, 1,560 fathoms depth, but all the Atlantis 

 records are from outside the Gulf area so appar- 

 ently the species is not common there. 



2 Molpadia cubatia Deichtnann 



FIQ. 68: 21-22. 



Trochostoma antarcticum Thdel, 1886a, p. 16. 

 Nee T. antarcticum Th^el, 1886a, p. 44, pi. 2, fig. 7. 

 Molpadia cubana Deichmann, 1940, p. 220, pi. 37. figs. 

 1-3. 



Diagnosis. — Small species, less than 10 cm. 

 long, with numerous phosphatic bodies and three- 

 pillared tables with three large holes and a vary- 

 ing number of smaller holes. Tail with small 

 tables with round to oblong disk with numerous 

 holes. Type: Museum of Comparative Zoology. 

 Type locality: Off Havana, 175-210 fathoms. 

 Distribution: So far reported only from the waters 

 around Cuba, off Yucatan and the coast of Texas. 

 From about 200 fathoms (Atlantis) ; a single rec- 

 ord from 1,440 fathoms may possibly be omitted 

 as erroneous. Along the coast of Texas and on 

 the shrimp grounds off Yucatan the species has 

 been taken in less than 50 fathoms depth (13 to 

 37 fathoms, Hildebrand, letter). 



3 Molpadia barbouri Deichmann 



Molpadia barbouri Deichmann, 1940, p. 222, pi. 39, figs. 

 1-6. 



Diagnosis. — Medium sized, 8 cm. long, with 

 snow-white skin (in alcohol). Rigid from the 

 numerous spicules which consist of three-pillared 

 tables with disk varying from large with several 

 circles of holes to smaller with few holes. Some- 

 times the spire is reduced so large plates result. 



Tail with small tables with elongate disk and 

 minute spire. Type: Museum of Comparative 

 Zoology. Type locality: Nicholas Channel, north 

 of Cuba. Distribution: Waters around Cuba, 

 from 390 to 605 fathoms. 



The majority of the Atlantis records are defi- 

 nitely outside the Gulf region, but nevertheless, 

 one may expect the species around the Yucatan 

 peninsula. 



Genus 2 PARACAUDINA Heding, 1931 



Caudina (partim) Auctores. 



Pseudocaudina Heding, 1931, p. 283 (preoccupied). 



Paracaudina Heding, 1931, p. 455. 



1 Paracaudina obesacauda (H. L. Clark) 



Caudina obesacauda H. L. Clark, 1907, pp. 38, 176, pi. 

 9, figs. 1-5; Deichmann, 1930, p. 201, pi. 24, figs. 6-8. 



Paracaudina obesacauda H. L. Clark, 1935, p. 284; 

 1940, p. 215. 



Diagnosis. — Up to 15 cm. long with the barrel- 

 shaped body gradually tapering off into the stout 

 tail. Spicules in skin numerous cross-cups, mostly 

 with bluntly rounded lateral projections, similar 

 to those found in the New Zealand species, P. 

 coriacea, and also common in the individuals of P. 

 chilensis from off the tropical west coast of 

 Central America and Mexico. Type: Museum 

 of Comparative Zoology. Type locality: Marco, 

 Florida. Distribution: Known from Key West 

 and Tortugas, Florida, westward to Galveston, 

 Texas. Few fathoms depth. 



Usually large numbers are dredged from the 

 same spot. More intensive collections will prob- 

 ably show that it is one of the most common 

 forms in the Gulf in suitable localities. Its 

 biology is completely unknown, but it will un- 

 doubtedly prove to be similar to that of the well 

 studied Japanese form, usually called P. ranson- 

 netti (v. Marenzeller) or P. chilensis (J. Muller)_ 



Order 5 APOD A Brandt, 1835 



KEY TO THE FAMILIES KNOWN FROM THE GULF OF MEXICO 



Spicules anchors and anchor plates; tentacles with .slender digits 1. Synaptidae, p. 406 



Spicules wheels and sigmoid or bracket-shaped bodies; tentacles with broad stem with short, flat digits 



2. Chiritotidae, p. 408 

 Family 1 SYNAPTIDAE Oestergren, 1898 



KEY TO THE GENERA AND SPECIES FOUND IN THE GULF OF MEXICO 



1. Deep water form with large anchors with teeth on the arms; anchor plates with numerous dentate holes. Tentacles 



witli one to two digits on each side. 4. Protankyra Oestergren Protankyra brychia (Verrill), p. 408 



1 . Shallow water forms 2 



