444 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Type, AHF no. 95. 



Type locality, Hancock Station 457-35, Secas Islands, Panama, 

 7°57'50''N, 82°01'15''W, 12 fms, several colonies on shells. 



Family RetepoHdae Smitt, 1867 



"Zooecia ovato-cylindrica secunda in stirpem reticulatam componun- 

 tur." This definition of the family by Smitt (1867:34) is very incom- 

 plete, since not all fenestrate bryozoans can be included in this family 

 and many which we now allocate here are not fenestrate. Levinsen 

 (1909:290) gives an extended definition from which we may sort out 

 the following essential characters: zooecia heavily calcified, with few 

 pores ; spines present or wanting ; a well-developed vestibular arch which 

 is usually beaded ; dependent avicularia of varying size and form (usually 

 a suboral one not in the midline) ; ovicell at first prominent but becom- 

 ing immersed, often with a median fissure, above the orifice a labellum 

 or prolongation (almost wanting in Rhynchozoon and Lepraliella in 

 which there is a triangular or semicircular area above the orifice con- 

 sisting of the endozooecial layer only). In the erect forms the zooecia 

 are all on the frontal side and the dorsal side is covered by a layer of 

 kenozooecia, which may or may not have pores and avicularia. Erect 

 species are usually fenestrate, sometimes forming a close network, (rete- 

 pores), but a few are merely branching or have only occasional fusions. 



Key to Genera of Reteporidae 



1. Zoarium erect, branching or fenestrate 2 



Zoarium encrusting 4 



2. Zoarium not fenestrate, or branches only occasionally joined ; 



ovicell with a median fissure Reteporellina 



Zoarium intricately fenestrate, forming a network; 



ovicell not fissured 3 



3. Front of ovicell complete, with a pointed labellum ; 



peristomes high obscuring aperture Phidolopora 



Front of ovicell incomplete above the aperture ; 



peristomes high only on the sides Schizoretepora 



4. Ovicell with a small median fissure; aperture with a 



narrow, slit-like sinus Schizotheca 



Ovicell with a subtriangular or semicircular area above the orifice 5 



