56 PEOCEEDINGS OF THE NATIONAL MUSEUM vol.72 



opesial cushion there is another exterior sclerite prolonged under the 

 valve up to the opesiule. This character is little visible on the photo- 

 graph, for it is manifested especially by a slight modification in the 

 color of the ectocyst. When the ectocyst is dried, it is supported 

 on the facettes of the frontal and assumes the aspect of Smitt's Fig- 

 ure 60 but with much less regularity; this appearance causes us to 

 suppose that it represents more the present species than that shown 

 in Figure 61. On the same dried ectocyst the trace of opesiular 

 muscles is indicated by two small concavities placed exactly at the 

 level of the opesiular indentations. 



The onychocellarium is provided with a large bimembranous man- 

 dible. The membrane is very thin and oval. When the mandible 

 is raised it hides a part of the distal zooecium; when it is lowered it 

 hides entirely the cryptocyst of the onychocellarium^ and the rachis 

 is inserted in the groove which separates the two proximal zooecia; 

 the free portion of the rachis is very flexible and takes different forms. 

 Two vigorous pairs of muscles move the mandible. Each onycho- 

 cellarium is fundamentally pentagonal, for it is always adjacent to 

 five zooecia. It is only very exceptionally and in the vicinity of the 

 ancestrula that it is lozenge-shaped and adjacent to four zooecia. 



Biology. — The ectocyst alone is colored yellow. Our living spec- 

 imens were in reproduction from January to May, 1885. We have 

 not found parasites on the living specimens. 



Aijinities. — This species differs from Velumella pusilla, new species, 



in its much larger dimensions and in the large oval membranes of the 



mandibles. It differs from Rectonychocella elongata of the Miocene of 



North Carolina in the constant presence of opesiular indentations. 



Occurrence.— Albatross Station D. 2319, north of Cuba; 23° 10' 37" 



N.; 82° 20' 06'' W.; 143 fms.; gray coral. 



Albatross Station D. 2322, north of Cuba; 23° 10' 



54" N.; 82° 17' 45" W.; 115 fms.; coral. 

 Albatross Station D. 2405, Gulf of Mexico; 28° 45' 

 00" N.; 85° 02' 00" W.; 30 fms.; gray sand, 

 broken coral. 

 Fowey Light, 15 miles south of Miami, Fla., 64 miles 

 from Florida; 77 meters (Smitt), Tortugas; low 

 water to 24 meters (Osburn). 

 Cotypes.— Cut. No. 7612, U.S.N.M. 



Subfamily Microporidae Hincks, 1880 



Genus DACRYONELLA Canu and Bassler, 1917 

 The polypidian convexity protrudes very little and is inconstant. 

 The opesiules are large, round, lateral indentations. The ovicell is 

 endozooecial. There are no opesial processes (therefore an opercular 



' This phenomenon is general in all the Opesiulidae. We have found it in the mandibular opercula 

 of Steganoporclla and in opercular mandibles of Siphonoporella. 



