﻿Rare 
  species 
  of 
  North 
  American 
  Diatomaceae 
  

  

  Charles 
  S. 
  Boyer 
  

   (with 
  plate 
  2) 
  

  

  Auliscus 
  floridanus 
  sp. 
  nov. 
  

  

  Valves 
  subtriangular. 
  Central 
  space 
  not 
  evident. 
  Surface 
  

   of 
  the 
  valve 
  plane, 
  imllstinctly 
  pruinose 
  for 
  two 
  thirds 
  of 
  the 
  

   radius 
  and 
  abruptly 
  costate 
  near 
  the 
  border, 
  with 
  sharply 
  defined, 
  

   coarse 
  costae 
  at 
  irregular 
  intervals, 
  parallel 
  between 
  the 
  processes 
  

   but 
  converging 
  near 
  them. 
  Processes 
  three, 
  close 
  to 
  the 
  border, 
  

   irregular 
  or 
  triangular, 
  with 
  hyaline 
  margins. 
  Diameter 
  70 
  /x. 
  

  

  [Fig. 
  3.] 
  

  

  Type 
  locality: 
  Mosquito 
  Inlet, 
  Florida. 
  

  

  Distribution: 
  marine: 
  known 
  from 
  the 
  type 
  locality 
  only. 
  

  

  Auliscus 
  hyalinus 
  sp. 
  nov. 
  

  

  Valve 
  subcircular, 
  plane, 
  slightly 
  irregular. 
  Central 
  space 
  

   appearing 
  hyaline, 
  about 
  one 
  third 
  the 
  diameter 
  of 
  the 
  valve, 
  

   indistinctly 
  granular 
  or 
  pruinose 
  toward 
  the 
  border 
  where 
  finely 
  

   punctate, 
  subtle, 
  radiating 
  striae 
  are 
  interspersed 
  at 
  irregular 
  

   intervals 
  with 
  delicate, 
  costate 
  lines. 
  Processes 
  three, 
  with 
  

   hyaline 
  borders, 
  placed 
  at 
  irregular 
  intervals 
  at 
  a 
  distance 
  from 
  

   the 
  border 
  greater 
  than 
  their 
  diameter, 
  indistinctly 
  granular. 
  

   Diameter 
  86 
  /x. 
  [Fig. 
  4.] 
  

  

  Type 
  locality: 
  Savin 
  Rock, 
  Connecticut. 
  

  

  Distribution: 
  marine; 
  known 
  from 
  the 
  type 
  locality 
  only. 
  

  

  The 
  granulation 
  of 
  the 
  surface 
  is 
  somewhat 
  similar 
  to 
  that 
  of 
  

   A. 
  puhinattis 
  Grun. 
  orA.Le 
  Tournetirii 
  Brun, 
  except 
  at 
  the 
  border. 
  

  

  Dimerogranuna 
  intermedium 
  sp. 
  nov. 
  

   Valves 
  rhombic-lanceolate. 
  Pseudoraphe 
  indistinct. 
  Striae 
  

   ten 
  In 
  lo 
  n, 
  moniliform. 
  Apices 
  indistinctly 
  punctate. 
  Length 
  of 
  

  

  valve 
  35 
  /i. 
  [Fig. 
  ii.] 
  

  

  Type 
  locality: 
  Campeche 
  Bay, 
  Mexico. 
  

  

  Distribution: 
  marine; 
  known 
  from 
  the 
  type 
  locality 
  only. 
  

  

  full' 
  

  

  D. 
  minus 
  (Greg.) 
  Ralfs. 
  

  

  67 
  

  

  